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Minnesota's Marsh Lake project getting back on track

This fixed structure dam impounds the waters in Marsh Lake and prevents the natural riverine system from experiencing the fluctuating water levels important for aquatic vegetation while also impeding natural fish migration. This lowhead dam will be replaced by a fish passage that will allow fish migration. Tom Cherveny / Forum News Service1 / 5

Walt Gessler, manager of the Lac qui Parle refuge, said the Marsh Lake project will restore the area to a natural riverine environment. One of the important goals is to restore the aquatic vegetation that once made the lake a mecca for migrating waterfowl, and the hunters who pursue them. Tom Cherveny / Forum News Service2 / 5

Working behind a coffer dam, workers are preparing the area where the Marsh Lake dam will be replaced with a variable flow structure that will allow for periodic drawdowns of the lake. Work on the structure is expected to begin in June. Tom Cherveny / Forum News Service 3 / 5

An angler on the east bank and pelicans are targeting fish below the Marsh Lake dam. One of the goals of the project is to increase the diversity and population of game fish in Marsh Lake and reduce the rough fish population. Tom Cherveny / Forum News Service 4 / 5

This backwater area downstream and east of the current Marsh Lake dam will be restored as the Pomme de Terre River's natural outlet into the Minnesota River. Tom Cherveny / Forum News Service5 / 5

APPLETON, Minn.—One of western Minnesota's largest ecosystem restoration projects is making "slow but steady progress,'' in the words of Walt Gessler, manager of the Lac qui Parle refuge with the Minnesota Department of Natural Resources.

The U.S. Army Corps of Engineers and the DNR are working to restore the ecological integrity of Marsh Lake, west of Appleton. The $12.93 million project aims to clear the turbid and largely rough-fish-dominated waters of the 5,000-acre lake in the Upper Minnesota River Valley.

"Weather challenges certainly slowed progress,'' said Shahin Khazrajafari, project manager with the U.S. Army Corps of Engineers.

High water flows, particularly those that occurred last autumn, delayed construction, which began in March 2017. The project contractors were unable to install a water control structure in the dike last year as planned. That work will begin this month, according to Khazrajafari.

The control structure is a critical part of the project. It will allow the DNR to periodically draw down the lake to mimic what normally would occur in what is a riverine system. Drawing down the water at the onset of winter will allow emergent vegetation to re-establish itself in the spring. It also will help knock down carp populations, said Gessler. Currently, carp represent about two-thirds of the fish biomass in the lake.

One goal of the restoration project is to improve the diversity and number of game fish in the lake, especially walleye and northern pike, said Gessler. Equally important is the goal to restore the aquatic vegetation and return the water body to its role as a feeding and resting area for migrating waterfowl.

Just over two decades ago, sago pondweed grew thick enough in parts of the lake to stop a motorboat. In the last couple of years, however, the DNR has not been able to find any pondweed, according to Gessler.

Khazrajafari said workers are hoping to begin work later this year on a fish passage in place of the existing, fixed-crest dam. Essentially a sloped, series of steps like a natural rapids, the passageway will allow fish to migrate upstream from Lac qui Parle Lake to reach food and spawning habitat in Marsh Lake.

Sometime next year, Khazrajafari said workers also will breach the dike at the site and allow the Pomme de Terre River to return to its natural outlet below the Marsh Lake dam. That will reduce the sediment load in Marsh Lake and allow greater fish migration.

Overall, this is one of the most cost-effective restoration projects in terms of its ecological benefits. Its cost is about 5 percent of the average cost for habitat restoration, Khazrajafari noted.

The Pomme de Terre River was rerouted and the existing, fixed-crest dam was installed as part of the Lac qui Parle Flood Control and Water Conservation Project launched in the 1930s. It impounded the waters and created Marsh Lake. Until that point, the riverine area was described as an area of potholes and sloughs. Now it's an open expanse of wind-churned waters where nutrients and sediments are kept in suspension and feed summer algal blooms.

It remains an important area for wildlife. Islands and a peninsula on the lake serve as the nesting area for one of the largest colonies of white pelicans in Minnesota.

Along with improving water quality, the project also will provide better access for people. The project includes development of a new access road to the site from the north. The DNR plans to eventually develop a pedestrian/bicycle trail to the site, either along the new road or by using the existing road from the east, according to Jeremy Losinski, parks and trails supervisor with the DNR for the region.

Workers will be installing concrete abutments when the new fish passage is added. The abutments will make it possible to someday construct a pedestrian/bicycle bridge over the fish passage and the spillway at the site.

The existing parking area on the east side will remain, and a new parking area will be added to the west side. Gessler said he believes the project will help make Marsh Lake a very popular destination.

Although the weather has made the project a challenge, Khazrajafari said he remains hopeful of seeing completion in June or July 2019.